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角规蓄积量观测值经常偏低,从而限制了它的实际应用。偏低原因何在?估计很多:下木遮蔽视线、观测部位偏高、角规缺口宽度(角规断面积常数)……。现将1977年农林部委托东北林学院举办的“全国伐区调查训练班”关于角规缺口宽度试验一例简报如下,供参考。试验区位于东北林学院凉水实验林场(黑龙江带岭)。试验小班面积30.3公顷,树种组成7红1云1冷1桦+水榆色杨,林分平均胸径32厘米,活立木每公顷蓄积量322米~3,林地地形平缓。试验选用两种缺口:1和2厘米(尺长均50厘米)。角规断面积常数分别为1和4(即每测一株断面积相应增加1和4米~2)。全小班
Angular gauge volume observations often low, thus limiting its practical application. Low reason for what? Estimated a lot: under the wood cover the line of sight, the observation area is high, angle gauge gap width (angular constant area) ... .... Now in 1977 the Ministry of Agriculture and Forestry commissioned by the Northeast Forestry College held a “national cutting survey training course” on the angle gauge notch width test a briefing below, for reference. Experimental area is located in Northeast Forestry College cold water experimental forest farm (Heilongjiang Belt). Test small class area of 30.3 hectares, tree species composition 7 red 1 cloud 1 cold 1 birch + water Ulmus, average diameter of 32 cm stand, living wood stock volume per hectare 322 m ~ 3, flat terrain. Two gaps were chosen for the test: 1 and 2 cm (50 cm length). The angular constant area is 1 and 4, respectively (ie 1 and 4 m ~ 2 for each cross-sectional area tested). Full small class